CPUs being used in portable mobile devices such as notebooks or smart phones have been developed for power savings with low-power and low-voltage models but at the same time required current and power consumption increases in response to demands for high-end features and multi-functions thereof.
A great deal of development researches has been continuously under way on DC-DC convertible inductors with smaller sizes and thinner systems while maintaining high-current and low-resistance.
Various ferrites or soft magnetic metals such as soft magnetic metal powders have been used in manufacturing miniaturized inductors to cope with high frequencies. Such materials are used independently but recently composite metal powders have been used to cope with high efficiency of inductors. The interests have been focused on improvements of uniform soft magnetic properties, low eddy current loss, low core loss at a high frequency and thermal properties.
However, since amount of soft magnetic metals used per an inductor decreases with getting smaller and thinner sizes of the inductor, the magnetic property is lowered. Thus, there is a demand to develop materials which maintain high magnetic properties at a high frequency as an operating frequency of an inductor installed in devices becomes higher.
In the inductor using soft magnetic metal powders, Fe-based soft magnetic metal powders such as Fe, Fe—Ni, Fe-based amorphous, or Fe—Ni—Cr crystalline soft magnetic metal powders are used. It is important to increase the density of materials to obtain high magnetic properties in miniaturized inductors. However, it is difficult to have sufficient packing density of metal powders due to the volume of binders or the pores inevitably generated between powders. Such a lowered packing density further causes reduction in the magnetic property, particularly in the permeability, and deteriorated performance of the inductors.
The prior art is ferromagnetic powder for dust core in KR Patent No. 2002-0037776.